The Syrian Observatory for Human Rights, a Britain-based monitoring group, said Sunday that Syrian rebels had locked people in cages and driven them to areas near Damascus to use them as human shields against heavy government air raids. A video posted online by Syria’s Shaam News Network showed men and women in iron cages. They were being driven on the back of pickup trucks through what it said was the area northeast of the capital. CCTV was unable to independently verify the video footage.